1. Field of the Invention
The present invention relates to an image pickup device, a camera module and a camera system.
2. Description of the Related Art
A camera module using an image pickup device has been recently required to be installed in a camera system containing a signal processing system in a compact information terminal such as a personal computer, a portable videophone, etc., and in order to satisfy this requirement, the camera module has been increasingly and strongly required to be designed in a compact size.
FIG. 6 shows one of conventional camera modules each using an image pickup device such as a CCD image pickup device, a CMOS image pickup device or the like. A camera module 51 shown in FIG. 6 comprises an image pickup device 52, a mounting board 53 and a lens unit 54. The image pickup device 52 is designed in a QFP (Quad Flat Package) type structure in which a chip-type image pickup device 55 is mounted in a package body 56 and hermetically sealed with seal glass 57. The image pickup device 52 is mounted on the mounting board 53 through external connecting lead terminals 58 provided at the four sides of the package body 56. The lens unit 54 is mounted at the upper portion of the image pickup device 52. The lens unit 54 comprises a holder 59, a mirror barrel 60, an optical filter 61 and a lens 62.
The thickness of the conventional module 51 is equal to the total thickness of the image pickup device 52, the mounting board 53, and the lens unit 54 which constitute the camera module 51. Therefore, in order to manufacture a low-profile camera module 51 (i.e., a camera module having a small thickness), it is necessary to reduce the thickness of each constituent part.
Under the present condition, the upper limit of reducing the thickness of each of the image pickup device 52, the mounting board 53 and the lens unit 54 is about to be reached.
Therefore, according to an aspect of the present invention, there is provided an image pickup device including: a light-transmissible board having a wiring pattern formed on one surface thereof and containing an optical filter; and an image pickup element having a photodetecting portion formed on one surface thereof, the image pickup element being mounted on the one surface of the light-transmissible board in a flip-chip style so that the photodetecting portion of the image pickup element is opposed to an area where the wiring pattern is unformed.
In the image pickup device thus constructed, the image pickup device is mounted in the flip-chip style on one surface of the light-transmissible board on which the wiring pattern is formed, thereby reducing the overall thickness of the image pickup device. Further, the light-transmissible board is provided with an optical filter function (for example, an infrared ray cutting function). Therefore, when a lens unit is mounted on the other surface of the light-transmissible board to fabricate a camera module, it is unnecessary to install an optical filter board in the lens unit.
According to another aspect of the present invention, there is provided a camera module which includes: a light-transmissible board having a wiring pattern formed on one surface thereof and containing an optical filter, an image pickup element having a photodetecting portion formed on one surface thereof, the image pickup element being mounted on the one surface of the light-transmissible board in a flip-chip style so that the photodetecting portion of the image pickup element is opposite an area where no circuit pattern is formed; and a lens unit mounted on the other surface of the light-transmissible board so as to be located above the photodetecting portion of the image pickup element.
Further, according to another aspect of the present invention, there is provided a camera system using the camera module having the above construction.
In the camera module thus constructed, and the camera system using the camera module, the image pickup element is mounted in the flip-chip style on the surface of the light-transmissible board on which the wiring pattern is formed, and the lens unit is mounted on the opposite surface of the light-transmissible board. Thus, the thickness of the image pickup device can be reduced to be less than that of the conventional module structure by the amount corresponding to the thickness of the package, to hermetically seal the image pickup element. Further, the constituent parts (the light-transmissible board, the image pickup element and the lens unit) constituting the image pickup device can be arranged densely in the thickness direction of the module.